Electrically controlled safety igniter circuit for gas burners



-r 1957 H. E. MORRISON ELECTRICALLY CONTROLLED SAFETY IGNITER CIRCUITFORGAS BURNERS Filed Feb. 9, 1953 In v'n L72 r f/aro/J/Vorrz $022mzmcoqmum mm b EE 2,812,806 Patented Nov. 12, 1957 ELECTRICALLYCONTROLLED SAFETY IGNITER CIRCUIT FOR GAS BURNERS Harold E. Morrison,St. Joseph, Mich., assignor, by mesne assignments, to WhirlpoolCorporation, a corporation of Delaware Application February 9, 1953,Serial No. 335,646

6 Claims. (Cl. 158-124) trolled by an electrical circuit so arranged asto instantaneously close the gas supply and prevent unburned gas frompassing through the main burner upon interruption of the electriccircuit.

A further object of my invention is to provide an automatic gas ignitercircuit in which a master valve is opened through the cold contact of aflame detector switch and a main burner valve is opened through the hotcontact of the flame detector switch, having an electrical interlockpreventing opening of the master valve upon a power interruption exceptthrough the cold contact of the flame detector switch.

A further object of my invention is to provide a simplified and novelform of control for an automatic gas pilot so arranged as to render itimpossible to supply gas to the main burner when the pilot is out.

Still another object of my invention is to provide an automatic igniterfor gas burners having an electrical in terlock for the master valve inthe gas supply line, maintaining the valve closed upon powerinterruption until the system is sufliciently cool to safely turn on thegas.

Still another object of my invention is to provide an igniter circuitfor a main gas burner including a flame detector switch having hot andcold contacts connected to initially turn on a master burner valve whenthe flame detector switch is in its cold position, and to hold the mainburner valve out of the circuit until the pilot burner has been ignited,and including a shut-E switch connected in the energizing circuit forthe burner valves, biased to energize the solenoid for a master gassupply valve through the cold contacts of the flame detector switch andmovable to connect the solenoid of the master gas supply valve toby-pass the flame detector switch upon opening of said valve, andlockingthe master gas supply valve from. opening when the supply ofpower has been interrupted and is again turned on, except through thecold contacts of the flame detector switch.

These and other objects of my invention will appear from time to time asthe following specification proceeds and with reference to theaccompanying drawing which diagrammatically shows an automatic ignitercircuit constructed in accordancewith my invention.

In the embodimentof my invention illustrated in the drawing, the ignitersafety circuit of my invention is shown as being operative to ignite andcontrol the operation of the master valve and main burner valve. of aclothes drier, although it need not be in such a circuit and maytrolling the supply of gas to a main burner 16. A pilot 123,018, filedon October 22, 1949 by Peter E. Geldhof and Harold E. Morrison, andentitled Gas Heated Drier and now Patent No. 2,635,354, dated April 21,1953 so the drier and the circuit therefor, need only be describedherein in sufii-cient detail to make my present invention readilyunderstandable.

A gas supply line 10 is shown as delivering gas to a master gas supplyvalve 11 operated to open upon energization of acoil 12 of a solenoid. Apipe 13 connects the master valve 11 with a main burner valve 15conburner 17 leads from the supply side of the main burner valve 15 to aposition adjacent the burner 16, for igniting said burner when the valve15 is turned on. The pilot burner 17 is controlled by the master valve11 and is supplied with gas when the valve 11 is, open. The pilot burner17 is shown as being ignited by a glow coil 19 energized by thesecondary 20 of a transformer 21.

While I have herein shown a glow coil for igniting the pilot burner 17,it should be understood that a glow coil need not be employed to ignitesaid pilot, but that the pilot may be ignited by an interrupted sparktype of igniter or by any other suitable igniting means and may even beignited by hand if desired. The glow coil 19 is positioned adjacent thepilot 17, but for convenience in illustrating the control circuit, isshown as being remote from said pilot. The main burner valve 15 is shownas being solenoid operated, and as opening upon the energization of acoil 23 of the solenoidtherefor.

The valves .11 and 15 may be of any well known form of solenoid operatedgas control valve, one form of valve construction being illustrated inmy 'joint application with .Peter E. Geldhof, Serial No. 123,018 and nowPatent No. 2,635,354, dated April 21, 1953 referred to before. Thestructure of said valves is no part of my present invention so need notherein be shown or described in de tail.

The supply of electric power to the operative components of the clothesdrier shown as being enclosed in a diagrammatic box D is eifectedthrough a pair of conductors 26 and 27.

An indicator light 35 is also shown as: being connected in the circuitthrough a terminal 39 of a flame detector switch 40, and lighting when acontact arm 41 of the flame detector switch moves into position tocomplete a circuit through a contact 43 of said switch, which ishereinafter referred to as the hot contact thereof. The indicator light35 thus indicates when the main burner valve is on.

A conductor 44 leads from the contact 43 of the flame detecting switch40 and is connected with the coil 23 of the solenoid for operating themain burner valve 15. A conductor 45 connects said coil to the contact36 of the timer switch 34. An adjustable thermostat 47, which may bemanually set to control the drier temperature is connected in theconductor 45 to break the circuit therethrough and shut ofi the mainburner valve when the temperature within the drier drum reaches thetemperature for which said adjustable thermostat is set.

A primary coil 53 of the transform-er 21 is initially connected in theenergizing circuit through the conductor 51 and a contact 54 of theflame detecting switch 40. The connection from the cold contact 54includes a conductor 55 leading from said cold contact and having aconductor 56 connected thereto which in turn is connected to oneterminal of the coil 53. The other terminal of the coil 53 is connectedwith the conductor 27 through a conductor 57, contacts 59 of a warpswitch 60 and a conductor 61, connected to the conductor 37. A heatercoil 63 is shown as being connected in parallel with the primary 53 ofthe transformer 21 and as being energized upon the energizing of saidprimary, to open the contacts of the warp switch 59 by resistor heatafter a predetermined time interval, which may be from 3 to 5 minutes atnormal voltages.

The coil 12 of the solenoid for opening the master valve 11 is shown asbeing energized through the cold Y contact 54 of the flame detectorswitch 40 by a conductor 63a, connected with a contact 64 of a shut-offswitch 65. The shut-01f switch 65 may be a well known form of quickacting shut-off switch having a contact arm 66 normally biased tocomplete a circuit from the contact 64 to the coil 12. The quickshut-off switch 65 is shown as being moved to complete a circuit througha contact 67 connected with the conductor 51 by operation of an armature69 for the solenoid operating the valve 11,

upon the energization of the coil 12 and opening of the master valve 11.Thus when the flame detector switch 40 is in position to complete acircuit through its contact arm 41 and cold contact 54, the coil 12 willbe energized. This will immediately break the circuit through thecontact 64 and complete a circuit to a contact 67, holding said coilenergized through the conductor 51. The circuit from the coil 12 toconductors 61 and 27 is shown as comprising a conductor 70 connectedwith the conductor 57, the contacts 59 of the warp switch 60 when saidwarp switch is in a closed position, and the timer switch 34.

The warp switch 60 is provided to deenergize the coil '12 for thesolenoid of the master supply valve 11 and shut off the supply of gas tothe pilot burner 17 and main burner valve in the event the flamedetector switch should not pass from its hot to its cold position, aswhen said warp switch by resistor heat in a time interval which may befrom three to five minutes should the switch arm 41 fail to move out ofengagement with the cold contact 54 into engagement with the hot contact43,

as by failure of the pilot to ignite, as previously mentioned. Uponopening of the circuit through the contacts 59 of the warp switch 60 byresistor heat, the conductor 55, cold contact 54 and contact arm 41 ofthe flame detector switch will short circuit the coil 12 from theenergizing circuit and the main or master burner 11 will go off byde-energization of the coil 12. occurs, the armature 69 of the solenoidoperating said master burner valve will release an arm 71 of the quickshut-oif switch 65 and said switch will move to its biased position andcomplete a circuit through the contact 64 and contact arm 66 thereof.When the quick shut-off switch 65 is in this position, the coil 12 canonly be energized and the master valve 11 can only be open when theflame detector switch 40 is in position to complete a circuit throughits contact arm 41 and cold contact 54.

In order to ignite the pilot burner 17 and the main burner 16 when thesolenoid 12 has been de-energized by failure of the pilot burner toignite and the contacts 59 'of the warp switch are maintained open bythe heater coil 63, the circuit to the dryer must be opened as byopening of the switch 34, to allow the time-delay warp switch 60 to cooland close the contacts 59, after which the switch 34 may again be closedand the burner circuit is in condition to ignite the pilot burner.

The flame detector switch 46 may be of a type similar to that shown anddisclosed in my joint application with 'P. E. Geldhof, Serial No.123,018 and now Patent No.

2,635,354, dated April 21, 1953 previously mentioned, wherein the heatof the pilot flame will move the contact arm 41 into position to close acircuit through the hot contact 43 of said switch and complete a circuitfrom the conductor 51 to the conductors 45 and 27.

When this This will energize the coil 23 and open the main burner valve15. Thus when the pilot burner 17 has been ignited the main burner valve16 can only open when the heat of the flame has moved the contact arm 41into engagement with the hot contact 43.

The instant, however, a power interruption occurs, the coils 23 and 12will be de-energized. This will shut ofl the master valve 11 and thesupply of gas to the pilot burner 17 and the main burner valve 15. Itwill also shut off'the main burner valve 15. De-energizing of the coil12 will also release the quick shut-off switch 65. Said switch will thenmove to its biased position to complete a circuit through the contact 64and cold contact 54 of the flame detecting switch 40 to the coil 12.When the quick shut-oflf switch 65 is in the position just men tioned.,the coil 12 can only be energized through the cold contact 54 of theflame detecting switch 46. The main or master supply valve, therefore,cannot be opened to supply gas to the pilot 17 and main burner 15 untilthe main and pilot burners have cooled sufficient- 1y to accommodate thecontact arm 41 to move from its hot to its cold position.

In operation, the contacts 59 of the warp switch 60 .are normally closedand the movable contact 41 is en gaged with the cold contact 54. Whenthe switch 34 and the door switch 29 have been closed, the solenoid coil12, the transformer primary 53, and the coil 63 of the timed delay orwarp switch 60 will all be connected in parallel between the supplylines 27 and 51. The master gas supply valve 11 will then be opened andgas will be supplied to the pilot burner 17. Upon opening of the mastergas supply valve 11, the switch arm 66 of the quick shut-off switch 65will move into engagement with the contact 67 and hold the solenoidenergized through the conductor 51. In normal operation the gas issuingfrom the pilot burner 17 will be ignited by the glow coil 19 and theheat of the pilot burner flame will move the movable contact arm 41 ofthe flame detecting switch 40 out of engagement with the cold contact 54into engagement with the hot contact 43 of said flame detecting switch.The solenoid coil 23 of the main burner valve 41, the conductor 45, thethermostat 47, the switch 34 and conductor 27. The main burner valve 15will then open to supply gas to the main burner 16.

If, for any reason, the pilot burner should fail to ignite, the heatercoil 63 of the time-delay or warp switch 60 will open its contact 59after a predetermined time interval. When this occurs, the solenoid coil12 as well as the primary 53 of the transformer 21 will be de-energizedand the contacts 59 will be maintained in open position.

The quick shut-off switch 65 will also be released, and the contact arm66 thereof will move to its biased position into engagement with thecontact 64. The solenoid coil 12 thereof cannot again be energized untilthe contact arm 41 has moved into position to engage the cold contact54, and the contacts 59 of the warp switch 60 have been closed. In orderto again ignite the burner, the switch 34 must be opened to allow thetime-delay or warp switch 60 to cool and close a circuit through thecontacts 59 thereof. The switch 34 may then be closed.

The solenoid coil 12 may then be energized, opening the main burner 11and engaging the contact arm 65 with the contact 67 to maintain thesolenoid coil 12 energized and the main burner valve 11 open. The mainburner will then be ignited and the circuit will be re-established, aspreviously described.

It may be seen from the foregoing that a simplified igniter circuit forgas burners has been provided, instantaneously shutting off the supplyof gas to the main burner upon a power failure and holding the supply ofgas shut off until the flame detecting switch has passed to position toclose a circuit through its cold contacts and turning on the supply ofgas to the pilot burner only through the'cold contacts of the flamedetecting switch; and holding the main burner valve closed until thepilot burner has been ignited a suflicient length of time to move thecontact arm of the flame detector switch 40 to engage the contact 43thereof and complete a circuit through the hot contacts of said switch.

It will be understood that various modifications and variations of thepresent invention may be effected without departing from the spirit andscope of the novel concepts thereof.

I claim as my invention:

1. A gas burner circuit comprising a main gas burner having a gas supplyline connected thereto, master and main burner solenoid opearted valvesin said supply line, a flame detector switch having hot and coldcontacts, an energizing circuit to the solenoid of said master valvethrough the cold contact of said flame detector switch, an energizingcircuit to the solenoid of said main burner valve through the hotcontact of said flame detector switch, a main line energizing circuitconnected with said flame detector switch, and the circuit from the coldcontact of said flame detector switch including a shut-oil switch,biased to complete a circuit to the solenoid for said master valvethrough the cold contact of said flame detector switch and operated uponenergization of said solenoid for said master valve, to break thecircuit through said cold contact and connect said solenoid for saidmaster valve directly to said main line energizing circuit until a powerinterruption, and moving to its biased position upon a powerinterruption and holding said solenoid for said master valve out of theenergizing circuit except through the cold contact of said flamedetector switch.

2. A gas burner circuit comprising a main gas burner having a gas supplyline connected thereto, a master solenoid-operated valve in said supplyline, a main burner solenoid-operated valve in said supply line, a pilotburner in said supply line on the supply side of said main burner valve,a flame detector switch having hot and cold contacts and moving from aposition closing a circuit from a main line circuit through its coldcontact to a position closing a circuit from the main line circuitthrough its hot contact by the presence of a pilot flame, an energizingcircuit to the solenoid of said master valve through the cold contact ofsaid flame detector switch, an energizing circuit to the solenoid ofsaid burner valve through the hot contact of said flame detector switch,and the energizing circuit to said solenoid for said master valveincluding a shut-off switch biased to complete a circuit to saidsolenoid through the cold contact of said flame detector switch andmoved by opening of said master valve to by-pass said cold contact andconnect said solenoid for said master valve directly with the main linecircuit upon energization of said solenoid for said master valve, andmoving back to its biased position upon a power interruption.

3. In an automatic gas igniter, a gas supply line having a main burnervalve therein and a master valve on the supply side of said main burnervalve, for controlling the supply of gas to said main burner valve, apilot burner on the supply side of said main burner valve and thedownstream side of said master valve, individual solenoids for each ofsaid valves energizable to open the same, an energizing circuit for saidsolenoids including a flame detector switch having hot and coldcontacts, the hot contacts of said flame detector switch being connectedto energize the solenoid for said main burner valve, a warp switchhaving contacts connected in series with the sole noid coil for saidmaster valve to energize said coil when the contacts of said warp switchare closed and said flame detector switch is in position to close thecircuit through its cold contacts, a heater coil energized through thecold contacts of said flame detector switch and opening said warp switchby resistor heat, to shunt said solenoid coil for said master valve outof the energizing circuit and shut oil the supply of gas upon thefailure of said pilot burner to ignite, and the energizing circuit tosaidsolenoid for said master valve also including a shutofl switchhaving two contacts, one connecting said solenoid coil with the coldcontacts of flame detector switch and the other being connected directlyin the energizing circuit and connecting said solenoid coil for saidmaster valve in the energizing circuit upon the energization of saidsolenoid coil,,said shut-ofl switch being biased to hold said solenoidfor said master valve out of the energizing circuit except through thecold contacts of said flame detecting switch whenever a powerinterruption occurs.

4. In a gas burner circuit, a main gas supply line, two valves connectedin series in said gas supply line, one being a master valve and theother being a main burner valve and being connected in said gas supplyline on the downstream side of. said master valve, a pilot burnerconnected in said gas supply line on the downstream side of said mastervalve and} the supply side of said main burner valve, individualsolenoids for each of said valves, energizable to open said valves, amain line conductor and a flame detector switch connected with said mainline conductor and having hot and cold contacts and a movable switch armmovable from a position in engagement with said cold contact intoengagement with said hot contact to complete a circuit from said mainline conductor through said hot contact to energize said solenoid forsaid main burner valve upon the presence of a pilot flame, a shut-offswitch connected in series with the cold contact of said flame detectorswitch for initially energizing said solenoid for said master valvethrough the cold contact of said flame detector switch, said shutoffswitch having two contacts, one being connected with the cold contact ofsaid flame detector switch and the other being connected directly withsaid main line conductor, said shut-off switch being biased to close acircuit through the cold contact of said flame detector switch and movedby the opening of said master valve upon energization of the solenoidtherefor to open the energizing circuit to said master valve through thecold contact of said flame detector switch and to maintain a holdingcircuit for the solenoid for said master valve through said main lineconductor, said shut-off switch moving back to its biased position anddeenergizing said solenoid for said master valve upon an interruption inthe energizing circuit, and holding said solenoid for said master valvedeenergized and maintaining said master valve closed until movement ofsaid flame detecting switch into position to close a circuit through itscold contact.

5. In a gas burner circuit, a gas supply line, two valves connected inseries in said gas supply line, one being a master valve and the otherbeing a main burner valve, the master valve being on the supply side ofsaid main burner valve and having a pilot burner connected therewith forigniting a main burner, individual solenoids for each of said valvesenergizable to open the same, a flame detector switch having hot andcold contacts and a movable switch arm engageable with the cold contactwhen the pilot is not lit and movable into engagement with the hotcontact to close a circuit therethrough by the heat of a pilot flame, amain line conductor connected with said movable switch arm, anenergizing circuit from said main line conductor to said solenoid forsaid master valve through said flame detector switch, the energizingcircuit to said solenoid for said master valve including a quickshut-oil switch operated by actuation of said master valve and havingtwo contacts and a contact arm connected with said solenoid for saidmaster valve, one of said contacts being electrically connected with thecold contact of said flame detector switch to energize said solenoid forsaid master valve through the cold contact of said flame detectorswitch, the other of said contacts being connected directly with saidmain line conductor to energize said solenoid for said master valvedirectly through said main line conductor upon movement of said mastervalve to an open position upon energization of the solenoid therefor,and means biasing said contact arm of said shutoff switch intoengagement with said one contact to close a circuit through the coldcontact of said flame detector switch upon a power interruption and thedeenergization of the solenoid for said master valve.

6. In a burner control system in combination, a pilot burner, a fuelcontrol means having in serial connection with one another a normallyclosed inlet valve, a normally closed outlet valve, and a main burnerfuel supply outlet, said fuel control means further including an outletbetween said inlet and outlet valves for supplying fuel to said pilotburner, whereby said inlet valve controls the flow of fuel to bothburners and said outlet valve controls the flow of fuel to the mainburner only when said inlet valve is open, an electromagnetic actuatorfor 'said inlet valve, an electromagnetic actuator for said outletposition to a hot position in response to a flame at said 2 pilotburner, a double throw switch operatively associated with said inletvalve actuator, said double throw switch being biased to one positionand being moved to its op posite position by said inlet valve actuatorwhen it is energized, an energizing circuit for said inlet valveactuator including said double throw switch when in its biased positionand said flame sensitiveswitch when in its cold position, an energizingcircuit for said igniter including said flame sensitive switch when inits cold position, an energizing circuit for said outlet valve actuatorincluding said flame sensitive switch whenin a hot position, and shuntmeans for maintaining an energizing circuit for said inlet valveactuator when said flame sensitive switch moves from said cold to saidhot position including said double throw switch when in its oppositeposition.

References Cited in the file of this patent UNITED STATES PATENTS2,269,157 Levine Jan. 6, 1942 0 2,327,690 Ackerman Aug. 24, 19432,456,147 Ray Dec. 14, 1948

